Army Cpl. Nicholas Wyatt Brett, 28, concluded a plea agreement Monday with state prosecutors, according to court documents. Brett was initially charged with first-degree and second-degree assault in the Aug. 6 attack on Airman 1st Class Seth Duggan, but admitted to committing third-degree assault.

That crime usually carries a maximum sentence of five years and a $50,000 fine, but under the terms of the agreement Brett agreed that his actions were “among the most serious conduct included in the definition of the offense.” That aggravating factor allows a judge to exceed the typical sentencing range .

Prosecutors said Brett was seen on surveillance video at F Street Station approaching Duggan from behind in the assault, at about 2:45 a.m. on a Sunday. Brett positioned Duggan’s head with his left hand before striking him with his right elbow, driving Duggan’s head into a metal bar – an impact which left Duggan using a cane, as he recovered from a fractured skull and traumatic brain injuries.

Court transcripts from a September bail hearing indicate that Brett and Duggan didn’t know each other prior to the assault. Arne Soldwedel, the prosecutor in the case, said Brett had gone to F Street “looking for trouble” and that a high-five had occurred after the attack.

Bouncers at F Street, Soldwedel said, didn’t do anything in response to the blow.

When asked if any changes have been made to security at the establishment since the assault, an F Street Station manager declined to comment.

Brett’s attorney at the time, Mary Burnell, said he would be kept on base during the assault case. His unit in JBER’s 4th Brigade Combat Team (Airborne), 25th Infantry Division deployed to Afghanistan last year.

Brett’s commanding officer, Army Capt. Herbert Boedecker, told the court the command was taking the incident seriously. A September memo from Boedecker laid out a weekday schedule for Brett, requiring him to be in specific areas of JBER and accountable to authorities at those buildings 24 hours a day.

“Brett will be in an authorized military uniform during the duty day and while using the physical fitness centers and dining facilities,” Boedecker wrote. “He will not operate a privately owned vehicle and he will not consume alcohol for the duration of his bail.”

Brett was granted a reduced bail of $2,500 in the wake of that hearing, and released to military supervision as the case approached a planned trial date next week. A judge ordered that he have no contact with Duggan or witnesses in the case.

Karen Kingston-Duggan, Duggan's mother, said she hadn't yet heard of the plea agreement Wednesday. Duggan’s family was planning to attend Brett's sentencing, initially set for Sept. 7.